Characterization of a cold-responsive gene, OsPTR1, isolated from the screening of β-glucuronidase (GUS) gene-trapped rice

T-DNA gene trap populations have been successfully used to isolate stress responsive genes by probing GUS expression after stress treatment. Here, we have identified cold responsive GUS expression in rice from Line 1C-118-30, where T-DNA was inserted at the 3rd exon of OsPTR1. This gene encodes a putative peptide transporter sharing 40% homology with Arabidopsis AtPTR2 and barley HvPTR. Northern analysis of OsPTR1 confirmed that OsPTR1 is inducible by cold stress, especially in the shoot but not in the root, thereby indicating an organ-specific response. Transcript was also induced by salt, and water stresses. Interestingly, OsPTR1 mRNA was highly expressed in the UBI::CBF1/DREB1b rice, indicating that OsPTR1 may be regulated by the CBF/DREB stress signaling pathway.